i joined this group because sometimes i prefer long games

but im not seeing any new open challenges..

does anyone knows why?

You could try to participate in the ladder tournament, or the  group matches (there aren't any at the moment, but appear regularly)

I've put out a new team-match challenge, I expect that will produce a new opportunity with a few days. ;)

In fact, we have a scheduled match already:

http://www.chess.com/groups/team_match.html?id=60293